首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1篇
  完全免费   1篇
  物理学   2篇
  2018年   1篇
  2017年   1篇
排序方式: 共有2条查询结果,搜索用时 31 毫秒
1
1.
Myoglobin has important biological functions in storing and transporting small diatomic molecules in human body. Two possible orientations of carbon monoxide (CO) in the heme distal pocket (named as B1 and B2 states) of myoglobin have been experimentally indicated. In this study, ab initio quantum mechanics/molecular mechanics (QM/MM) molecular dynamics simulation of CO in myoglobin was carried out to investigate the two possible B states. Our results demonstrate that the B1 and B2 states correspond to Fe…CO (with carbon atom closer to iron center of heme) and Fe…OC (with oxygen atom closer to Fe), by comparing with the experimental infrared spectrum. QM electrostatic polarization effect on CO brought from the protein and solvent environment is the main driving force, which anchors CO in two distinctive orientations and hinders its rotation. The calculated vibrational frequency shift between the state B1 and B2 is 13.1 cm-1, which is in good agreement with experimental value of 11.5 cm-1. This study also shows that the electric field produced by the solvent plays an important role in assisting protein functions by exerting directional electric field at the active site of the protein. From residue-based electric field decomposition, several residues were found to have most contributions to the total electric field at the CO center, including a few charged residues and three adjacent uncharged polar residues (namely, HIS64, ILE107, and PHE43). This study provides new physical insights on rational design of enzyme with higher electric field at the active site.  相似文献
2.
上转换发光纳米颗粒是一类遵循反斯托克斯原理的新型发光材料,具有发光强度高、发光稳定、无组织背景荧光、无光漂白、低毒性以及较好的生物相容性等优点,其激发光为红外或者近红外光,活体组织穿透深度高,在生物医学检测、诊断以及疾病治疗等方面均具有潜在的应用价值。磁共振成像是目前医学临床常用的影像检测手段之一,具有软组织成像质量高、空间分辨率高、无辐射、无损伤等优点,在心脑血管、肿瘤等疾病的影像诊断方面具有重要作用。本文将聚焦于近年来稀土上转换发光纳米材料在磁共振影像方面的研究进展,通过介绍磁共振成像机理、磁共振造影剂的构建、上转换发光纳米材料的设计及在磁共振医学影像、疾病治疗等方面的应用,并结合我们课题组基于UCNP医学磁共振多模态影像的相关研究进展,对上转换发光纳米颗粒在磁共振成像方面的应用研究进行探讨和展望。  相似文献
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号